---

yaml
---
r: 257017
b: refs/heads/master
c: facc430
h: refs/heads/master
i:
  257015: d57b0f6
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9137fb28ac74d05eb66d1d8e6778eaa14e6fed43
+refs/heads/master: facc43071cc0d4821c176d7d34570714eb348df9

trunk/kernel/events/core.c

@@ -200,6 +200,22 @@ __get_cpu_context(struct perf_event_context *ctx)
 	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
 }
 
+static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
+			  struct perf_event_context *ctx)
+{
+	raw_spin_lock(&cpuctx->ctx.lock);
+	if (ctx)
+		raw_spin_lock(&ctx->lock);
+}
+
+static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
+			    struct perf_event_context *ctx)
+{
+	if (ctx)
+		raw_spin_unlock(&ctx->lock);
+	raw_spin_unlock(&cpuctx->ctx.lock);
+}
+
 #ifdef CONFIG_CGROUP_PERF
 
 /*
@@ -340,11 +356,8 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
 	rcu_read_lock();
 
 	list_for_each_entry_rcu(pmu, &pmus, entry) {
-
 		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
 
-		perf_pmu_disable(cpuctx->ctx.pmu);
-
 		/*
 		 * perf_cgroup_events says at least one
 		 * context on this CPU has cgroup events.
@@ -353,6 +366,8 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
 		 * events for a context.
 		 */
 		if (cpuctx->ctx.nr_cgroups > 0) {
+			perf_ctx_lock(cpuctx, cpuctx->task_ctx);
+			perf_pmu_disable(cpuctx->ctx.pmu);
 
 			if (mode & PERF_CGROUP_SWOUT) {
 				cpu_ctx_sched_out(cpuctx, EVENT_ALL);
@@ -372,9 +387,9 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
 				cpuctx->cgrp = perf_cgroup_from_task(task);
 				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
 			}
+			perf_pmu_enable(cpuctx->ctx.pmu);
+			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 		}
-
-		perf_pmu_enable(cpuctx->ctx.pmu);
 	}
 
 	rcu_read_unlock();
@@ -1759,15 +1774,14 @@ static void ctx_sched_out(struct perf_event_context *ctx,
 {
 	struct perf_event *event;
 
-	raw_spin_lock(&ctx->lock);
 	ctx->is_active = 0;
 	if (likely(!ctx->nr_events))
-		goto out;
+		return;
+
 	update_context_time(ctx);
 	update_cgrp_time_from_cpuctx(cpuctx);
-
 	if (!ctx->nr_active)
-		goto out;
+		return;
 
 	perf_pmu_disable(ctx->pmu);
 	if (event_type & EVENT_PINNED) {
@@ -1780,8 +1794,6 @@ static void ctx_sched_out(struct perf_event_context *ctx,
 			group_sched_out(event, cpuctx, ctx);
 	}
 	perf_pmu_enable(ctx->pmu);
-out:
-	raw_spin_unlock(&ctx->lock);
 }
 
 /*
@@ -1929,8 +1941,10 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
 	rcu_read_unlock();
 
 	if (do_switch) {
+		raw_spin_lock(&ctx->lock);
 		ctx_sched_out(ctx, cpuctx, EVENT_ALL);
 		cpuctx->task_ctx = NULL;
+		raw_spin_unlock(&ctx->lock);
 	}
 }
 
@@ -2056,10 +2070,9 @@ ctx_sched_in(struct perf_event_context *ctx,
 {
 	u64 now;
 
-	raw_spin_lock(&ctx->lock);
 	ctx->is_active = 1;
 	if (likely(!ctx->nr_events))
-		goto out;
+		return;
 
 	now = perf_clock();
 	ctx->timestamp = now;
@@ -2074,9 +2087,6 @@ ctx_sched_in(struct perf_event_context *ctx,
 	/* Then walk through the lower prio flexible groups */
 	if (event_type & EVENT_FLEXIBLE)
 		ctx_flexible_sched_in(ctx, cpuctx);
-
-out:
-	raw_spin_unlock(&ctx->lock);
 }
 
 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
@@ -2110,6 +2120,7 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
 	if (cpuctx->task_ctx == ctx)
 		return;
 
+	perf_ctx_lock(cpuctx, ctx);
 	perf_pmu_disable(ctx->pmu);
 	/*
 	 * We want to keep the following priority order:
@@ -2124,12 +2135,14 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
 
 	cpuctx->task_ctx = ctx;
 
+	perf_pmu_enable(ctx->pmu);
+	perf_ctx_unlock(cpuctx, ctx);
+
 	/*
 	 * Since these rotations are per-cpu, we need to ensure the
 	 * cpu-context we got scheduled on is actually rotating.
 	 */
 	perf_pmu_rotate_start(ctx->pmu);
-	perf_pmu_enable(ctx->pmu);
 }
 
 /*
@@ -2269,7 +2282,6 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
 	u64 interrupts, now;
 	s64 delta;
 
-	raw_spin_lock(&ctx->lock);
 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
 		if (event->state != PERF_EVENT_STATE_ACTIVE)
 			continue;
@@ -2301,24 +2313,19 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
 		if (delta > 0)
 			perf_adjust_period(event, period, delta);
 	}
-	raw_spin_unlock(&ctx->lock);
 }
 
 /*
  * Round-robin a context's events:
  */
 static void rotate_ctx(struct perf_event_context *ctx)
 {
-	raw_spin_lock(&ctx->lock);
-
 	/*
 	 * Rotate the first entry last of non-pinned groups. Rotation might be
 	 * disabled by the inheritance code.
 	 */
 	if (!ctx->rotate_disable)
 		list_rotate_left(&ctx->flexible_groups);
-
-	raw_spin_unlock(&ctx->lock);
 }
 
 /*
@@ -2345,6 +2352,7 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 			rotate = 1;
 	}
 
+	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
 	perf_pmu_disable(cpuctx->ctx.pmu);
 	perf_ctx_adjust_freq(&cpuctx->ctx, interval);
 	if (ctx)
@@ -2370,6 +2378,7 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 		list_del_init(&cpuctx->rotation_list);
 
 	perf_pmu_enable(cpuctx->ctx.pmu);
+	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 }
 
 void perf_event_task_tick(void)
@@ -2424,9 +2433,9 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)
 	 * in.
 	 */
 	perf_cgroup_sched_out(current);
-	task_ctx_sched_out(ctx, EVENT_ALL);
 
 	raw_spin_lock(&ctx->lock);
+	task_ctx_sched_out(ctx, EVENT_ALL);
 
 	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
 		ret = event_enable_on_exec(event, ctx);
@@ -5982,6 +5991,7 @@ static int pmu_dev_alloc(struct pmu *pmu)
 }
 
 static struct lock_class_key cpuctx_mutex;
+static struct lock_class_key cpuctx_lock;
 
 int perf_pmu_register(struct pmu *pmu, char *name, int type)
 {
@@ -6032,6 +6042,7 @@ int perf_pmu_register(struct pmu *pmu, char *name, int type)
 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
 		__perf_event_init_context(&cpuctx->ctx);
 		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
+		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
 		cpuctx->ctx.type = cpu_context;
 		cpuctx->ctx.pmu = pmu;
 		cpuctx->jiffies_interval = 1;
@@ -6776,14 +6787,14 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
 	 * our context.
 	 */
 	child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
-	task_ctx_sched_out(child_ctx, EVENT_ALL);
 
 	/*
 	 * Take the context lock here so that if find_get_context is
 	 * reading child->perf_event_ctxp, we wait until it has
 	 * incremented the context's refcount before we do put_ctx below.
 	 */
 	raw_spin_lock(&child_ctx->lock);
+	task_ctx_sched_out(child_ctx, EVENT_ALL);
 	child->perf_event_ctxp[ctxn] = NULL;
 	/*
 	 * If this context is a clone; unclone it so it can't get